compare -b -t "oct28relZ.tex" "oct31relJ.tex" File #1: oct28relZ.tex File #2: oct31relJ.tex Nonmatching lines (File "oct28relZ.tex"; Line 1:19; File "oct31relJ.tex"; Line 1:32) 1 \documentstyle[11pt]{article} 2 %\documentstyle[fullpage,11pt,amssymbols]{article} 3 %\input{BoxedEPS} 4 %\HideDisplacementBoxes 5 %\SetOzTeXEPSFSpecial 6 %\marginparwidth 0pt 7 %\oddsidemargin 0pt 8 %\evensidemargin 0pt 9 %\marginparsep 0pt 10 11 \topmargin 0pt 12 13 %\textwidth 6.5in 14 %\textheight 8.5 in 15 %\input{amssym.def} 16 17 \input{diagrams} % Paul Taylor's Macro Package 18 \begin{document} 19 1 \documentclass{article} 2 \textwidth 130mm 3 \textheight 200mm 4 \renewenvironment{abstract}{\section*{Abstract}\small}{} 5 \newtheorem{definition}{Definition} 6 \newtheorem{example}[definition]{Example} 7 \newtheorem{application}[definition]{Application} 8 \newtheorem{theorem}[definition]{Theorem} 9 \newtheorem{exercise}[definition]{Exercise} 10 \newtheorem{lemma}[definition]{Lemma} 11 \newtheorem{notation}[definition]{Notation} 12 \newtheorem{observation}[definition]{Observation} 13 \newtheorem{proposition}[definition]{Proposition} 14 \newtheorem{proposal}[definition]{Proposal} 15 \newtheorem{remark}[definition]{Remark} 16 \newtheorem{result}[definition]{Result} 17 \newtheorem{conjecture}[definition]{Conjecture} 18 \newtheorem{claim}[definition]{Claim} 19 \newtheorem{assumption}[definition]{Assumption} 20 \newtheorem{corollary}[definition]{Corollary} 21 \makeatletter 22 \renewcommand{\@begintheorem}[2]{ % not in italics 23 \trivlist\item[\hskip\labelsep{\bf #1\ #2}]} 24 \renewcommand{\@opargbegintheorem}[3]{\trivlist 25 \item[\hskip \labelsep{\bf #1\ #2\ (#3)}]} 26 \makeatother 27 \newtheorem{proof}{Proof} 28 \renewcommand{\theproof}{} % no numbers on proofs 29 % End of preamble 30 \usepackage{latexsym} 31 \input{diagrams} % Paul Taylor's Macro Package 32 \begin{document} Extra lines in 1st before 54 in 2nd (File "oct28relZ.tex"; Line 41; File "oct31relJ.tex"; Line Æ54) 41 Nonmatching lines (File "oct28relZ.tex"; Line 46:67; File "oct31relJ.tex"; Line 58:60) 46 47 48 49 50 \newcommand{\doar}{\mbox {$\,\ \rightarrow\kern-0.7em\rightarrow\ $}} 51 52 \newtheorem{thm}{Theorem}[section] 53 \newtheorem{lem}[thm]{Lemma}% [section] 54 \newtheorem{cor}[thm]{Corollary}% [section] 55 \newtheorem{ex}[thm]{Example}% [section] 56 \newtheorem{rem}[thm]{Remark}% [section] 57 \newtheorem{nota}[thm]{Notation}% [section] 58 \newtheorem{prop}[thm]{Proposition}% [section] 59 \newtheorem{deff}[thm]{Definition}% [section] 60 61 %%%%\newtheorem{proof}{Proof} 62 %\newenvironment{proof}{{\it Proof:}}{{\it Q.e.d.}} 63 \newenvironment{akn}{\noindent{\bf Acknowledgments }}{} 64 \newenvironment{proof}{\noindent{\bf Proof }}{} 65 66 67 \newcommand{\notation}{{\bf Notation }} 58 \newcommand{\doar}{\mbox {$\,\ \rightarrow\kern-0.7em\rightarrow\ $}} 59 60 \newcommand{\notationn}{{\bf Notation }} Extra lines in 1st before 70 in 2nd (File "oct28relZ.tex"; Line 77:78; File "oct31relJ.tex"; Line Æ70) 77 \newenvironment{prsk}{\noindent{\bf Proof sketch }}{} 78 \newenvironment{altpr}{\noindent{\bf Alternative proof }}{} Extra lines in 1st before 81 in 2nd (File "oct28relZ.tex"; Line 90; File "oct31relJ.tex"; Line Æ81) 90 \newcommand{\eclas}[1]{\mbox{$\langle{#1}\rangleÄ$}} Extra lines in 1st before 114 in 2nd (File "oct28relZ.tex"; Line 124; File "oct31relJ.tex"; Line Æ114) 124 Nonmatching lines (File "oct28relZ.tex"; Line 131:149; File "oct31relJ.tex"; Line 120) 131 \newcommand{\bd}{\begin{deff}\em} 132 \newcommand{\bdl}[1]{\begin{deff}\em\label{#1}} 133 \newcommand{\bl}{\begin{lem}\em} 134 \newcommand{\bll}[1]{\begin{lem}\em\label{#1}} 135 \newcommand{\bp}{\begin{prop}\em} 136 \newcommand{\bpl}[1]{\begin{prop}\em\label{#1}} 137 \newcommand{\bt}{\begin{thm}\em} 138 \newcommand{\btl}[1]{\begin{thm}\em\label{#1}} 139 \newcommand{\bel}[1]{\begin{ex}\em\label{#1}} 140 \newcommand{\bc}{\begin{cor}\em} 141 \newcommand{\bcl}[1]{\begin{cor}\em\label{#1}} 142 \newcommand{\bproof}{\begin{proof}} 143 \newcommand{\eproof}{\end{proof}} 144 \newcommand{\ed}{\end{deff}} 145 \newcommand{\el}{\end{lem}} 146 \newcommand{\ep}{\end{prop}} 147 \newcommand{\et}{\end{thm}} 148 \newcommand{\ee}{\end{ex}} 149 \newcommand{\ec}{\end{cor}} 120 Extra lines in 2nd before 163 in 1st (File "oct28relZ.tex"; Line Æ163; File "oct31relJ.tex"; Line 134) 134 \newcommand{\richard}[1]{\{{\bf Zurab:~\sf #1}\}} % Highlight text. Nonmatching lines (File "oct28relZ.tex"; Line 177:180; File "oct31relJ.tex"; Line 149:152) 177 We impose on $\stab$ natural \emph{stability} conditions, that are 178 \zurab{sufficient} for each term not in $\stab$ to have at least one 179 $\stab$-needed redex, and for repeated 180 contraction of $\stab$-needed redexes in a term $t$ to lead to a 149 We impose natural \emph{stability} conditions on $\stab$, that 150 guarantee that each term not in $\stab$ has at least one 151 $\stab$-needed redex, such that repeated 152 contraction of $\stab$-needed redexes in a term $t$ will lead to a Nonmatching lines (File "oct28relZ.tex"; Line 185; File "oct31relJ.tex"; Line 157) 185 head-normal-forms, and weak head-normal-forms, in the \lc, are all stable 157 head-normal forms, and weak head-normal forms, in the \lc, are all stable Nonmatching lines (File "oct28relZ.tex"; Line 214:215; File "oct31relJ.tex"; Line 186:187) 214 -- a redex with at least one \zurab{contracted \emph{residual}} in 215 any reduction to normal 186 -- a redex with at least one contracted \emph{residual} in 187 every reduction to normal Nonmatching lines (File "oct28relZ.tex"; Line 218:220; File "oct31relJ.tex"; Line 190:192) 218 to its normal form whenever there is one; we refer to it as the 219 \emph{Normalization Theorem}. They also define the class of \emph{strongly 220 sequential} OTRSs where a needed redex can efficiently be found in any 190 to its normal form whenever there is one; we refer to this as the 191 \emph{Normalization Theorem}. They also define the class of \emph{strongly 192 sequential} OTRSs where a needed redex can be found efficiently in any Nonmatching lines (File "oct28relZ.tex"; Line 238:253; File "oct31relJ.tex"; Line 210:225) 238 defined \zurab{the \emph{essential} strategy} for the 239 $\lambda$-calculus~\cite{[colog]}, OTRSs~\cite{[rta]}, and \emph{Expression 240 Reduction Systems} (OERSs)~\cite{[caap]}. The strategy contracts 241 \emph{essential} redexes -- the redexes that have \emph{descendants} under 242 any reduction. The notion of descendant is a refinement of that of 243 \emph{residual} -- the descendant of a contracted redex is its contractum, 244 while it does not have residuals.\footnote{\zurab{Decsendants and residuals 245 are sometimes used as synonyms, which we think is not justified.}} 246 Hence, essentiality makes sense for all subterms, not only for redexes. 247 In~\cite{[Mar]}, Maranget introduces a different notion of neededness, 248 where a redex $u$ is needed if it has a residual under any reduction that 249 does not contract the residuals of $u$. This neededness notion makes sense 250 also for terms that do not have a normal form, and coincides with the 251 notion of essentiality. 252 253 Sekar and Ramakrishnan~\cite{[SeRa]} study a normalizing 210 defined the \emph{essential} strategy for the 211 $\lambda$-calculus~\cite{[colog]}, OTRSs~\cite{[rta]}, and \emph{Expression 212 Reduction Systems} (OERSs)~\cite{[caap]}. This strategy contracts 213 \emph{essential} redexes -- the redexes that have \emph{descendants} under 214 every reduction. The notion of descendant is a refinement of 215 \emph{residual} -- the descendant of a contracted redex is its contractum, 216 while it does not have residuals.\footnote{\john{Note that descendants and residuals 217 are sometimes treated as synonymous in the literature.}} 218 Essentiality makes sense for all subterms, not only redexes. 219 In~\cite{[Mar]}, Maranget introduces a different notion of neededness, 220 where a redex $u$ is needed if it has a residual under any reduction that 221 does not contract residuals of $u$. This neededness notion makes sense 222 even for terms that do not have a normal form, and coincides with the 223 notion of essentiality. 224 225 Sekar and Ramakrishnan~\cite{[SeRa]} study a normalizing Nonmatching lines (File "oct28relZ.tex"; Line 260; File "oct31relJ.tex"; Line 232) 260 inessential subterms (i.e., the garbage) in simply typable $\lambda$-terms. 232 inessential subterms (i.e., the garbage) in simply typeable $\lambda$-terms. Nonmatching lines (File "oct28relZ.tex"; Line 274:276; File "oct31relJ.tex"; Line 246:248) 274 terms of different shapes (\zurab{e.g., weak-head-normal forms, 275 constructor head-normal forms,} etc.) as the 276 results, it is natural to ask what properties a set of terms must possess 246 terms of different shapes (weak-head-normal forms, 247 constructor head-normal forms, etc.) as the 248 results of computation , it is natural to ask what properties a set of terms must possess Extra lines in 2nd before 280 in 1st (File "oct28relZ.tex"; Line Æ280; File "oct31relJ.tex"; Line 252:253) 252 \john{Would it open a can of worms to talk of infinite reductions? We can compute to whnf even when no nf exists.} 253 Nonmatching lines (File "oct28relZ.tex"; Line 293:304; File "oct31relJ.tex"; Line 267:276) 293 We impose a natural condition on $\stab$, called \emph{stability}, which is 294 \zurab{sufficient} for each term not in $\stab$-normal form (i.e., 295 not in $\stab$) to have at least one $\stab$-needed redex, and repeated 296 contraction of $\stab$-needed redexes in a term $t$ to lead to an 297 $\stab$-normal form of $t$ whenever there is one. 298 A set $\stab$ of terms is stable if it is \emph{closed under parallel moves}: 299 for any $t\not\in \stab$, any $P:t\doar o\in \stab$, and any $Q:t\doar e$ 300 not containing terms in $\stab$, the final term of $P/Q$, the 301 \emph{residual} of $P$ under $Q$, is in $\stab$; and is \emph{closed under 302 unneeded expansion}: for any $e\red{u}o$ such that $e\not\in \stab$ and 303 $o\in \stab$, a residual of $u$ is contracted in any reduction from $e$ to 304 a term in~$\stab$.\footnote{When the rewrite system is non-duplicating 267 We impose a natural condition on $\stab$, \emph{stability}, which 268 guarantees that each term not in $\stab$-normal form (i.e., 269 not in $\stab$) has at least one $\stab$-needed redex, such that repeated 270 contraction of $\stab$-needed redexes in a term $t$ will lead to an 271 $\stab$-normal form of $t$ whenever there is one. 272 A set $\stab$ of terms is stable if it is \emph{closed under 273 unneeded expansion}: for any $e\red{u}o$ such that $e\not\in \stab$ and 274 $o\in \stab$, a residual of $u$ is contracted in any reduction from $e$ to 275 a term in~$\stab$; and is \emph{closed under reduction}: 276 for any $t\ar o$ where $t\in \stab$, then $o\in \stab$.\footnote{When the rewrite system is non-duplicating Extra lines in 2nd before 325 in 1st (File "oct28relZ.tex"; Line Æ325; File "oct31relJ.tex"; Line 297:303) 297 Although we claim that our definition of stability is the most natural that has been proposed, it is possible to weaken the conditions for stability and still retain the concept of relative neededness. For example, an alternative definition is explored in 298 \emph{closed under parallel moves}: 299 for any $t\not\in \stab$, any $P:t\doar o\in \stab$, and any $Q:t\doar e$ 300 not containing terms in $\stab$, the final term of $P/Q$, the 301 \emph{residual} of $P$ under $Q$, is in $\stab$. \john{Is it necessary to say 302 ``not containing terms in $\stab$'' for Q?} 303 Nonmatching lines (File "oct28relZ.tex"; Line 423:429; File "oct31relJ.tex"; Line 402:408) 423 The concepts introduced in Section~\ref{S.rel.need.} are taken 424 from~\cite{[ctrs]}, but the definitions are different in that 425 the new definitions use only the residual concept while the original 426 definitions are based on a concept of descendants for subterms and 427 components. \zurab{Furthermore, we have simplified the stability concept 428 (by secrifying the generality). Our labelling system in Section~\ref{S.labels} 429 is based on an unpublished work by Kennaway and Sleep~\cite{[K.S.]}.} 402 The concepts introduced in Section~\ref{S.rel.need.} build 403 on~\cite{[ctrs]}, but here the 404 definitions use only the residual concept while the earlier 405 definitions were based on a concept of descendants for subterms and 406 components. The stability concept is simpler, and hence slightly less general. 407 The labelling system in Section~\ref{S.labels} 408 \john{presents} unpublished work by Kennaway and Sleep~\cite{[K.S.]}. Extra lines in 2nd before 436 in 1st (File "oct28relZ.tex"; Line Æ436; File "oct31relJ.tex"; Line 415:416) 415 \section{Orthogonal Expression Reduction Systems} 416 \label{S.CRS} Extra lines in 1st before 419 in 2nd (File "oct28relZ.tex"; Line 438:444; File "oct31relJ.tex"; Line Æ419) 438 439 440 \section{Orthogonal Expression Reduction Systems} 441 \label{S.CRS} 442 443 444 Nonmatching lines (File "oct28relZ.tex"; Line 465; File "oct31relJ.tex"; Line 439) 465 \begin{deff}\em 439 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 478; File "oct31relJ.tex"; Line 452) 478 {\em metavariables} $A, B,\ldots$ that range over terms, but with an 452 \emph{metavariables} $A, B,\ldots$ that range over terms, but with an Nonmatching lines (File "oct28relZ.tex"; Line 484:485; File "oct31relJ.tex"; Line 458) 484 is a metaterm and $\theta$ is an assignment, then the $\theta$-{\em 485 instance} $t\theta$ of $t$ is the term obtained from $t$ by replacing 458 is a metaterm and $\theta$ is an assignment, then the $\theta$-\emph{instance} $t\theta$ of $t$ is the term obtained from $t$ by replacing Nonmatching lines (File "oct28relZ.tex"; Line 500; File "oct31relJ.tex"; Line 473) 500 \end{deff} 473 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 514; File "oct31relJ.tex"; Line 487) 514 \begin{deff}\em 487 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 545; File "oct31relJ.tex"; Line 518) 545 \end{deff} 518 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 548:549; File "oct31relJ.tex"; Line 521:522) 548 \zurab{For the sake of simplicity, below we restrict ourselves to 549 \emph{variable-capturte-free ERSs}, which are ERSs in which all 521 \zurab{Begin (} For the sake of simplicity, below we restrict ourselves to 522 \emph{variable-capture-free ERSs}, which are ERSs in which all Nonmatching lines (File "oct28relZ.tex"; Line 552:553; File "oct31relJ.tex"; Line 525:526) 552 CERSs}~\cite{[pun-ic]}. \footnote{\zurab{Roughly, 553 full extendeedness means that an erasing step cannot turn a non-redex 525 CERSs}~\cite{[pun-ic]}. Roughly, 526 full extendedness means that an erasing step cannot turn a non-redex Nonmatching lines (File "oct28relZ.tex"; Line 556:558; File "oct31relJ.tex"; Line 529:533) 556 can create an $\eta$-redex above the contractum. The full extendeedness 557 restriction is necessary for many important results in the theory 558 of higher-order rewriting, see e.g.~\cite{[Raa.th],[Oos],[Oos97],[pun-ic]}.}}} 529 can create an $\eta$-redex above the contractum. The full extendedness 530 restriction is necessary for many important results in the theory 531 of higher-order rewriting, see e.g.~\cite{[Raa.th],[Oos],[Oos97],[pun-ic]} 532 \zurab{) End}. 533 Nonmatching lines (File "oct28relZ.tex"; Line 564:566; File "oct31relJ.tex"; Line 539:541) 564 not really necessary -- free variables can be used instead, as in TRSs 565 (since (free) variables in TRS rules play the role of metavariables in ERS 566 rules). We will indeed do so at least when giving TRS examples. 539 not really necessary -- free variables can be used instead, as in TRSs, 540 since (free) variables in TRS rules play the role of metavariables in ERS 541 rules. We will indeed do so at least when giving TRS examples. Nonmatching lines (File "oct28relZ.tex"; Line 590; File "oct31relJ.tex"; Line 565) 590 \begin{nota}\em 565 \begin{notation} Nonmatching lines (File "oct28relZ.tex"; Line 597; File "oct31relJ.tex"; Line 572) 597 \end{nota} 572 \end{notation} Nonmatching lines (File "oct28relZ.tex"; Line 643; File "oct31relJ.tex"; Line 618) 643 The following \emph{strong Church-Rosser (confluence)} 618 The \emph{Strong Church-Rosser (confluence)} Nonmatching lines (File "oct28relZ.tex"; Line 651:659; File "oct31relJ.tex"; Line 626:634) 651 \begin{thm}\em 652 \label{T.FD.} 653 \zurab{All complete developments of a set of redexes in a term $t$, in an OERS, 654 end at the same term $s$, and the residuals of any redex in $t$ along 655 any complete development are the same redexes in~$s$.} 656 \end{thm} 657 658 659 \begin{thm}\em 626 \begin{theorem} 627 \label{T.FD.} 628 All complete developments of a set of redexes in a term $t$, in an OERS, 629 end at the same term $s$, and the residuals in~$s$ of any redex in $t$ along 630 any complete development are the same. 631 \end{theorem} 632 633 634 \begin{theorem} Nonmatching lines (File "oct28relZ.tex"; Line 663; File "oct31relJ.tex"; Line 638) 663 \end{thm} 638 \end{theorem} Nonmatching lines (File "oct28relZ.tex"; Line 691; File "oct31relJ.tex"; Line 666) 691 \bdl{D.exter.and.vanish.} 666 \begin{definition}\label{D.exter.and.vanish.} Nonmatching lines (File "oct28relZ.tex"; Line 694:713; File "oct31relJ.tex"; Line 669:688) 694 \item[(1)] We call $P:t\doar o$ \emph{external} to a redex $u\subt t$ 695 if $P$ does not \zurab{contract residuals} of~$u$. 696 697 \item[(2)] We call $P:t\doar o$ \emph{external} to a set of redexes 698 $U\subt t$ if $P$ is external to all $u\in U$. 699 700 \item[(3)] We say that $P$ \emph{$\stab$-suppresses} $u$ if $P$ is 701 $\stab$-normalizing and is external to~$u$. 702 703 \item[(4)] We say that $P$ \emph{erases} $u$ if $u/P=\emp$. Note that 704 contracting a redex erases it. 705 706 \item[(5)] We say that $P$ \emph{discards} $u$ if $P$ is external to $u$ and 707 $u/P=\emp$. 708 \end{enumerate} 709 \ed 710 711 712 713 \begin{deff}\em 669 \item[(1)] $P:t\doar o$ is \emph{external} to a redex $u\subt t$ 670 if $P$ does not contract any residual of~$u$. 671 672 \item[(2)] $P:t\doar o$ is \emph{external} to a set of redexes 673 $U\subt t$ if $P$ is external to all $u\in U$. 674 675 \item[(3)] $P$ \emph{$\stab$-suppresses} $u$ if $P$ is 676 $\stab$-normalizing and is external to~$u$. 677 678 \item[(4)] $P$ \emph{erases} $u$ if $u/P=\emp$. Note that 679 contracting a redex erases it. 680 681 \item[(5)] $P$ \emph{discards} $u$ if $P$ is external to $u$ and 682 $u/P=\emp$. 683 \end{enumerate} 684 \end{definition} 685 686 687 688 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 719:720; File "oct31relJ.tex"; Line 694:695) 719 starting from $t$ at least one of its residuals is contracted,} and call 720 \emph{$\Pi$-unneeded} otherwise. 694 starting from $t$ at least one of its residuals is contracted,} \john{Or: no reduction in $\Pi$ is external to $u$} and call 695 \emph{$\Pi$-unneeded} otherwise. \john{Or reverse the definition and say unneeded if some reduction is external to $u$.} Nonmatching lines (File "oct28relZ.tex"; Line 724:726; File "oct31relJ.tex"; Line 699:701) 724 denoted \emph{$\stab$-normalizing} reductions, \zurab{and we will call a term 725 $t$ \emph{$\stab$-normalizing} if there is an $\stab$-normalizing reduction 726 starting from $t$.} 699 denoted \emph{$\stab$-normalizing} reductions. A term 700 $t$ is denoted \emph{$\stab$-normalizing} if some $\stab$-normalizing reduction 701 starts at $t$. Nonmatching lines (File "oct28relZ.tex"; Line 731; File "oct31relJ.tex"; Line 706) 731 \end{deff} 706 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 747:749; File "oct31relJ.tex"; Line 722:724) 747 We will state the definition of the property of sets of terms for which 748 it is possible to generalise the Normalization Theorem and will then 749 give some examples showing why some intuitively simpler definitions 722 We will state conditions on sets of terms which guarantee that 723 a generalization of the Normalization Theorem will be satisfied. 724 We will give some examples showing why some intuitively simpler definitions Nonmatching lines (File "oct28relZ.tex"; Line 753; File "oct31relJ.tex"; Line 728) 753 \begin{deff}\em 728 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 756:757; File "oct31relJ.tex"; Line 731:732) 756 \item[(a)] $\stab$ \zurab{is \emph{closed under reduction}: if $t\in\stab$ 757 and $t\doar s$, then $s\in\stab$;} and 731 \item[(a)] $\stab$ is \emph{closed under reduction}: if $t\in\stab$ 732 and $t\doar s$, \john{$t\ar s$,} then $s\in\stab$; and Nonmatching lines (File "oct28relZ.tex"; Line 763; File "oct31relJ.tex"; Line 738) 763 \end{deff} 738 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 771:773; File "oct31relJ.tex"; Line 746:748) 771 TRSs~\cite{[Nok.thi.]}, and the set of root-stable forms (which are terms 772 that cannot be rewritten to a redex)~\cite{[Mid]}. All these sets are 773 closed under reduction, which implies closure under parallel moves. 746 TRSs~\cite{[Nok.thi.]}, and the set of root-stable forms (terms 747 that cannot be rewritten to a redex)~\cite{[Mid]}. All these sets are 748 closed under reduction \john{removed here: which implies closure under parallel moves}. Nonmatching lines (File "oct28relZ.tex"; Line 868; File "oct31relJ.tex"; Line 843) 868 \begin{ex}\em 843 \begin{example} Nonmatching lines (File "oct28relZ.tex"; Line 896; File "oct31relJ.tex"; Line 871) 896 \end{ex} 871 \end{example} Nonmatching lines (File "oct28relZ.tex"; Line 920:921; File "oct31relJ.tex"; Line 895:896) 920 Let there be a set ${\cal L}_0$ of {\em atomic labels}, 921 and a set ${\cal C}$ of {\em label constructors} in $1-1$ correspondence with 895 Let there be a set ${\cal L}_0$ of \emph{atomic labels}, 896 and a set ${\cal C}$ of \emph{label constructors} in $1-1$ correspondence with Nonmatching lines (File "oct28relZ.tex"; Line 933; File "oct31relJ.tex"; Line 908) 933 By a {\em labelled term} we mean any term which results from this 908 By a \emph{labelled term} we mean any term which results from this Nonmatching lines (File "oct28relZ.tex"; Line 949; File "oct31relJ.tex"; Line 924) 949 We now construct the set of {\em labelled rules}. 924 We now construct the set of \emph{labelled rules}. Nonmatching lines (File "oct28relZ.tex"; Line 959; File "oct31relJ.tex"; Line 934) 959 other than metasubstitutions, 934 except metasubstitutions, Nonmatching lines (File "oct28relZ.tex"; Line 964; File "oct31relJ.tex"; Line 939) 964 (This tuple of labels is called the {\em signature} of $f(s)$.) 939 (This tuple of labels is called the \emph{signature} of $f(s)$.) Nonmatching lines (File "oct28relZ.tex"; Line 1020; File "oct31relJ.tex"; Line 995) 1020 \begin{prop}\em 995 \begin{proposition} Nonmatching lines (File "oct28relZ.tex"; Line 1030:1036; File "oct31relJ.tex"; Line 1005:1011) 1030 \bproof 1031 Easy from definition of the labelling. 1032 \eproof 1033 \end{prop} 1034 1035 1036 \begin{cor}\em 1005 \begin{proof} 1006 Easy from definition of the labelling. 1007 \end{proof} 1008 \end{proposition} 1009 1010 1011 \begin{corollary} Nonmatching lines (File "oct28relZ.tex"; Line 1043:1045; File "oct31relJ.tex"; Line 1018:1020) 1043 \end{cor} 1044 1045 \begin{prop}\em 1018 \end{corollary} 1019 1020 \begin{proposition} Nonmatching lines (File "oct28relZ.tex"; Line 1050:1053; File "oct31relJ.tex"; Line 1025:1028) 1050 \bproof 1051 See~\cite{[Kl.CRS],[Mel],[Oos97]}. 1052 \eproof 1053 \end{prop} 1025 \begin{proof} 1026 See~\cite{[Kl.CRS],[Mel],[Oos97]}. 1027 \end{proof} 1028 \end{proposition} Nonmatching lines (File "oct28relZ.tex"; Line 1086; File "oct31relJ.tex"; Line 1061) 1086 \bll{L.external.rem.ext.} 1061 \begin{lemma}\label{L.external.rem.ext.} Nonmatching lines (File "oct28relZ.tex"; Line 1114; File "oct31relJ.tex"; Line 1089) 1114 \el 1089 \end{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1117; File "oct31relJ.tex"; Line 1092) 1117 \begin{cor}\em 1092 \begin{corollary} Nonmatching lines (File "oct28relZ.tex"; Line 1121; File "oct31relJ.tex"; Line 1096) 1121 \end{cor} 1096 \end{corollary} Nonmatching lines (File "oct28relZ.tex"; Line 1128; File "oct31relJ.tex"; Line 1103) 1128 \begin{lem}\em 1103 \begin{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1139; File "oct31relJ.tex"; Line 1114) 1139 \end{lem} 1114 \end{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1149; File "oct31relJ.tex"; Line 1124) 1149 \begin{thm}\em 1124 \begin{theorem} Nonmatching lines (File "oct28relZ.tex"; Line 1192; File "oct31relJ.tex"; Line 1167) 1192 \end{thm} 1167 \end{theorem} Nonmatching lines (File "oct28relZ.tex"; Line 1195; File "oct31relJ.tex"; Line 1170) 1195 \noindent\notation 1170 \noindent\notationn Nonmatching lines (File "oct28relZ.tex"; Line 1201; File "oct31relJ.tex"; Line 1176) 1201 \begin{lem}\em 1176 \begin{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1212; File "oct31relJ.tex"; Line 1187) 1212 \end{lem} 1187 \end{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1221; File "oct31relJ.tex"; Line 1196) 1221 \begin{prop}\em 1196 \begin{proposition} Nonmatching lines (File "oct28relZ.tex"; Line 1234; File "oct31relJ.tex"; Line 1209) 1234 \end{prop} 1209 \end{proposition} Nonmatching lines (File "oct28relZ.tex"; Line 1267; File "oct31relJ.tex"; Line 1242) 1267 \begin{ex}\em 1242 \begin{example} Nonmatching lines (File "oct28relZ.tex"; Line 1277; File "oct31relJ.tex"; Line 1252) 1277 \end{ex} 1252 \end{example} Nonmatching lines (File "oct28relZ.tex"; Line 1293; File "oct31relJ.tex"; Line 1268) 1293 \bd 1268 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1296; File "oct31relJ.tex"; Line 1271) 1296 \ed 1271 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1311; File "oct31relJ.tex"; Line 1286) 1311 \begin{deff}\em 1286 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1320; File "oct31relJ.tex"; Line 1295) 1320 \end{deff} 1295 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1334; File "oct31relJ.tex"; Line 1309) 1334 \begin{deff}\em 1309 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1374; File "oct31relJ.tex"; Line 1349) 1374 \end{deff} 1349 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1377; File "oct31relJ.tex"; Line 1352) 1377 \begin{lem}\em 1352 \begin{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1399; File "oct31relJ.tex"; Line 1374) 1399 \end{lem} 1374 \end{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1402; File "oct31relJ.tex"; Line 1377) 1402 \begin{lem}\em 1377 \begin{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1428; File "oct31relJ.tex"; Line 1403) 1428 \end{lem} 1403 \end{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1433; File "oct31relJ.tex"; Line 1408) 1433 \begin{thm}\em 1408 \begin{theorem} Nonmatching lines (File "oct28relZ.tex"; Line 1452; File "oct31relJ.tex"; Line 1427) 1452 \end{thm} 1427 \end{theorem} Nonmatching lines (File "oct28relZ.tex"; Line 1483; File "oct31relJ.tex"; Line 1458) 1483 \begin{deff}\em 1458 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1496; File "oct31relJ.tex"; Line 1471) 1496 \end{deff} 1471 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1504; File "oct31relJ.tex"; Line 1479) 1504 \bel{E.nne.per.sec.con.} 1479 \begin{example}\label{E.nne.per.sec.con.} Nonmatching lines (File "oct28relZ.tex"; Line 1562; File "oct31relJ.tex"; Line 1537) 1562 \ee 1537 \end{example} Nonmatching lines (File "oct28relZ.tex"; Line 1566; File "oct31relJ.tex"; Line 1541) 1566 \bll{L.prs.m-nee.sec.} 1541 \begin{lemma}\label{L.prs.m-nee.sec.} Nonmatching lines (File "oct28relZ.tex"; Line 1571; File "oct31relJ.tex"; Line 1546) 1571 \bproof 1546 \begin{proof} Nonmatching lines (File "oct28relZ.tex"; Line 1577:1578; File "oct31relJ.tex"; Line 1552:1553) 1577 \eproof 1578 \el 1552 \end{proof} 1553 \end{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1588; File "oct31relJ.tex"; Line 1563) 1588 \begin{deff}\em 1563 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1596; File "oct31relJ.tex"; Line 1571) 1596 \end{deff} 1571 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1617; File "oct31relJ.tex"; Line 1592) 1617 \begin{lem}\em 1592 \begin{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1629; File "oct31relJ.tex"; Line 1604) 1629 \end{lem} 1604 \end{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1643; File "oct31relJ.tex"; Line 1618) 1643 \begin{ex}\em 1618 \begin{example} Nonmatching lines (File "oct28relZ.tex"; Line 1672; File "oct31relJ.tex"; Line 1647) 1672 \end{ex} 1647 \end{example} Nonmatching lines (File "oct28relZ.tex"; Line 1687; File "oct31relJ.tex"; Line 1662) 1687 \begin{deff}\em 1662 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1694; File "oct31relJ.tex"; Line 1669) 1694 \end{deff} 1669 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1697; File "oct31relJ.tex"; Line 1672) 1697 \begin{deff}\em 1672 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1716; File "oct31relJ.tex"; Line 1691) 1716 \end{deff} 1691 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1719; File "oct31relJ.tex"; Line 1694) 1719 \bel{E.abs.una.} 1694 \begin{example}\label{E.abs.una.} Nonmatching lines (File "oct28relZ.tex"; Line 1729; File "oct31relJ.tex"; Line 1704) 1729 \ee 1704 \end{example} Nonmatching lines (File "oct28relZ.tex"; Line 1742; File "oct31relJ.tex"; Line 1717) 1742 \begin{prop}\em 1717 \begin{proposition} Nonmatching lines (File "oct28relZ.tex"; Line 1746; File "oct31relJ.tex"; Line 1721) 1746 \end{prop} 1721 \end{proposition} Nonmatching lines (File "oct28relZ.tex"; Line 1749; File "oct31relJ.tex"; Line 1724) 1749 \begin{lem}\em 1724 \begin{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1774; File "oct31relJ.tex"; Line 1749) 1774 \end{lem} 1749 \end{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1790; File "oct31relJ.tex"; Line 1765) 1790 \begin{prop}\em 1765 \begin{proposition} Nonmatching lines (File "oct28relZ.tex"; Line 1809; File "oct31relJ.tex"; Line 1784) 1809 \end{prop} 1784 \end{proposition} Nonmatching lines (File "oct28relZ.tex"; Line 1814; File "oct31relJ.tex"; Line 1789) 1814 \btl{T.qpmn.gen.min.str.} 1789 \begin{theorem}\label{T.qpmn.gen.min.str.} Nonmatching lines (File "oct28relZ.tex"; Line 1824; File "oct31relJ.tex"; Line 1799) 1824 \bproof 1799 \begin{proof} Nonmatching lines (File "oct28relZ.tex"; Line 1831:1832; File "oct31relJ.tex"; Line 1806:1807) 1831 \eproof 1832 \et 1806 \end{proof} 1807 \end{theorem} Nonmatching lines (File "oct28relZ.tex"; Line 1860; File "oct31relJ.tex"; Line 1835) 1860 \bd 1835 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1863; File "oct31relJ.tex"; Line 1838) 1863 \ed 1838 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1875; File "oct31relJ.tex"; Line 1850) 1875 \bt 1850 \begin{theorem} Nonmatching lines (File "oct28relZ.tex"; Line 1880; File "oct31relJ.tex"; Line 1855) 1880 \et 1855 \end{theorem} Nonmatching lines (File "oct28relZ.tex"; Line 1899; File "oct31relJ.tex"; Line 1874) 1899 \begin{deff}\em 1874 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1905; File "oct31relJ.tex"; Line 1880) 1905 \end{deff} 1880 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1909; File "oct31relJ.tex"; Line 1884) 1909 \begin{deff}\em 1884 \begin{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1919; File "oct31relJ.tex"; Line 1894) 1919 \end{deff} 1894 \end{definition} Nonmatching lines (File "oct28relZ.tex"; Line 1923; File "oct31relJ.tex"; Line 1898) 1923 \noindent\notation Below $FAM(P)$ will denote the set of families 1898 \noindent\notationn Below $FAM(P)$ will denote the set of families Nonmatching lines (File "oct28relZ.tex"; Line 1929:1931; File "oct31relJ.tex"; Line 1904:1906) 1929 \begin{lem}\em 1930 \label{L.fam.compl.} 1931 Every family is contracted at most once in any complete 1904 \begin{lemma} 1905 \label{L.fam.compl.} 1906 Every family is contracted at most once in a complete Nonmatching lines (File "oct28relZ.tex"; Line 1954; File "oct31relJ.tex"; Line 1929) 1954 \end{lem} 1929 \end{lemma} Nonmatching lines (File "oct28relZ.tex"; Line 1959; File "oct31relJ.tex"; Line 1934) 1959 \begin{thm}\em 1934 \begin{theorem} Nonmatching lines (File "oct28relZ.tex"; Line 1981; File "oct31relJ.tex"; Line 1956) 1981 \end{thm} 1956 \end{theorem} Nonmatching lines (File "oct28relZ.tex"; Line 2006; File "oct31relJ.tex"; Line 1981) 2006 $\reg$-minimal $\reg$-optimal semi-complete family-reduction. 1981 $\reg$-minimal $\reg$-optimal semi-complete family-reduction: Nonmatching lines (File "oct28relZ.tex"; Line 2009:2012; File "oct31relJ.tex"; Line 1984:1987) 2009 \begin{ex}\em 2010 \label{E.ers.min.opt.} 2011 Consider the OERS $R=\{\sigma x A B\ar \delta x 2012 (((A/x)B/x)A),\,\, f(A)\ar g(A,A)\}$, and let $\reg$ be the set of terms 1984 \begin{example} 1985 \label{E.ers.min.opt.} 1986 For the OERS $R=\{\sigma x A B\ar \delta x 1987 (((A/x)B/x)A),\,\, f(A)\ar g(A,A)\}$, let $\reg$ be the set of terms Nonmatching lines (File "oct28relZ.tex"; Line 2018; File "oct31relJ.tex"; Line 1993) 2018 left-spine redex, which do not exist in terms from $\reg$. Thus $\reg$ 1993 left-spine redex, which does not exist in terms from $\reg$. Thus $\reg$ Nonmatching lines (File "oct28relZ.tex"; Line 2038; File "oct31relJ.tex"; Line 2013) 2038 \end{ex} 2013 \end{example} Nonmatching lines (File "oct28relZ.tex"; Line 2047; File "oct31relJ.tex"; Line 2022) 2047 \begin{ex}\em 2022 \begin{example} Nonmatching lines (File "oct28relZ.tex"; Line 2077; File "oct31relJ.tex"; Line 2052) 2077 \end{ex} 2052 \end{example} Nonmatching lines (File "oct28relZ.tex"; Line 2080; File "oct31relJ.tex"; Line 2055) 2080 \begin{ex}\em 2055 \begin{example} Nonmatching lines (File "oct28relZ.tex"; Line 2092; File "oct31relJ.tex"; Line 2067) 2092 \end{ex} 2067 \end{example} Nonmatching lines (File "oct28relZ.tex"; Line 2109; File "oct31relJ.tex"; Line 2084) 2109 `(partial) results' should posses in order for the 2084 `(partial) results' should possess in order for the Nonmatching lines (File "oct28relZ.tex"; Line 2161:2162; File "oct31relJ.tex"; Line 2136) 2161 %\begin{akn} 2162 \section*{Acknowledgements} 2136 \section*{Acknowledgments} Nonmatching lines (File "oct28relZ.tex"; Line 2166:2170; File "oct31relJ.tex"; Line 2140:2141) 2166 discussions. \zurab{The annonymous referees provided valuable suggestions.} 2167 The diagrams were drawn using P.~Taylor's diagram package. 2168 2169 %\end{akn} 2170 2140 discussions. The referees provided valuable suggestions. 2141 The diagrams were drawn using P.~Taylor's diagram package. Nonmatching lines (File "oct28relZ.tex"; Line 2358:2359; File "oct31relJ.tex"; Line 2329:2330) 2358 normalization in orthogonal rewrite systems. \zurab{Information and 2359 Computation (to appear).} 2329 normalization in orthogonal rewrite systems. 2330 Information and Computation (to appear). Nonmatching lines (File "oct28relZ.tex"; Line 2362:2364; File "oct31relJ.tex"; Line 2333:2334) 2362 2363 \bibitem[{KP99}]{[KP99]} 2364 Khasidashvili Z., Piperno A. Normalization of typable terms by 2333 \bibitem[{KP99}]{[KP99]} 2334 Khasidashvili Z., Piperno A. Normalization of typeable terms by Extra lines in 1st file (File "oct28relZ.tex"; Line 2492:2494; File "oct31relJ.tex"; Line 2461Æ) 2492 2493 2494 *** EOF on both files ***